// { dg-do compile }// Copyright (C) 2003 Free Software Foundation, Inc.// Contributed by Nathan Sidwell 20 Apr 2003 <nathan@codesourcery.com>// PR 10337, unneeded warningclass A {  public:  A() {}};class B : public A {  public:  B() {}  void operator=(const A& b) {}  void operator=(const B& b) {}};class C {  public:  C() {}  operator B &() { return _b; }  operator const B &() const { return _b; }    B _b;};int main() {  B b;  C c;  b = c;}